High Sensitive Methods for Health Monitoring of Compressor Blades and Fatigue Detection

Table 2

The fatigue of metal compressor blades at numbers of load cycles in the range 10⁰–10¹² [69].

Number of cycles	Description
10^0–10^3	Low cycle quasi-static or fatigue fracture (LCF problem) at availability of large “microplastic” deformation in some zones of failure. The crack nucleation below the surface.
10^3–10^5	Low cycle fatigue fracture (LCF problem) at availability rather small “macroplastic” deformation in a zone of failure (when 𝜎𝑒≤𝜎𝑎≤𝜎𝑦,𝜎𝑒—a limit of elasticity). The crack nucleation from the surface.
10^5–10^8	Many classical cycles fatigue fracture (HCF problem) at availability of “microplastic” deformations in micro and macrovolumes near a zone of fatigue (when 𝜎𝑎 ≤ 𝜎𝑒). The crack nucleation from the surface.
10^9–10^12	Fatigue fracture on super high bases (VHCF problem) at availability of “microplastic” deformation in microvolumes near a zone of failure (when 𝜎𝑎≪𝜎𝑒). The crack nucleation on the soft inclusion below the surface.